Why we must invest in soil carbon storage

It may sound far-fetched, but it’s true – the top thirty centimetres of the earth’s soil contains almost twice the volume of carbon as in our atmosphere. But while we increasingly acknowledge the role of the oceans and trees for carbon storage, we often forget the huge potential of the ground beneath our feet.

To address this lapse of attention and raise awareness of the power of the soil, we will answer the following questions:

• How does soil carbon storage work?
• Why do we need healthy soils?
• What prevents effective soil carbon storage?
• How can we farm for soil health?
• How do our flagship portfolio projects work to improve soil health?

HOW DOES SOIL CARBON STORAGE WORK?

The world’s soils are inherently carbon-rich. On a basic level, as plants photosynthesise, they capture carbon which is, as they die and decompose, stored in the soil. However, human activity can also seriously alter the soil’s carbon content.

On the one hand, we can increase the ability of soils to capture carbon by planting crops. As they grow, these plants capture – or sequester – carbon dioxide from the atmosphere. This is transported through their intricate root systems and stored below the earth’s surface. But our growing needs for land and food are placing additional, excess pressure upon the earth. As forests are cleared and we turn to increasingly intensive agricultural practices, we prevent the soil from storing carbon at scale. With the climate crisis already at our door, destroying a natural method of carbon capture is extremely serious – we have no time to delay, we must invest to improve the health of the world’s soils.

WHY DO WE NEED HEALTHY SOILS?

Our soils are absolutely foundational to support life on earth. When soils are healthy, they contain the correct mix of nutrients and microbiology to support a region’s native plants. This, in turn, supports an area’s overall biodiversity as mammals, birds and insects can consume the nutrients they need. What’s more, soil can hold more water when it is healthy and uncompacted. This can improve water retention, serving to reduce risks of flooding.

But this is not all; when soil is in a state of good health, it offers extensive benefits for our climate. Globally, our soils could sequester and store carbon at such a scale as to be transformational to climate mitigation efforts.

There is an increasing scientific consensus that farming can play a pivotal role in soil carbon storage. For instance, Jacqueline McGlade – former chief scientist at the UN environment programme – estimates that improving agricultural practices can boost soil carbon storage. The study finds that enhancing the farming techniques on half of the world’s agricultural land so as to store just one percent more carbon, would be enough to create substantial change.

McGlade is not alone. Another study reports that if soil protection and restoration efforts were improved to the maximum, an additional 5.5 gigatonnes of CO2e could be sequestered and stored every year. However, other sources offer different estimates. Indeed, the NCS World Atlas – a tool developed by Nature4Climate and The Nature Conservancy to convey the potential of natural climate solutions for emissions reductions – considers 1-2 billion tonnes annually to be achievable. Although a smaller volume, the NCS World Atlas estimate is still a material amount – roughly equivalent to the entire annual emissions of Russia in 2020.

WHAT PREVENTS EFFECTIVE SOIL CARBON STORAGE?

The climate crisis poses a serious threat to soils. As temperatures rise and rainfall patterns change, soils can become dry, dusty and more likely to blow away. Not only does this limit the soil’s ability to capture and store carbon, it also reduces agricultural output. Without moisture, yields are lower, and more irrigation is required to keep farms productive. With the global population already exceeding 8 billion, maintaining (and increasing) the capacity of soil to produce food is critical for future food security.

With so many mouths to feed, it is understandable that much of the world has turned to intensive agriculture over the past decades. In the agricultural sector, many farmers remain financially (and culturally) tied to nitrogen fertilisers, the extensive application of pesticides and using land, seemingly ceaselessly, for production. But the over-cropping and overgrazing of farmland has caused nutrient depletion and soil degradation. Therefore, in a collective bid to increase agricultural productivity, we have actually further limited our ability to produce food in the long-term.

On a local scale, effective soil carbon storage can be prevented if farms operate from a place of financial insecurity. Without stable, steady incomes, transitioning to more sustainable agricultural practices can be unfeasible. However, financial incentive mechanisms could help farmers focus upon the health of their soils and shift to a more regenerative way of farming.

HOW CAN WE FARM FOR SOIL HEALTH?

Despite the increasing body of scientific evidence on soil carbon storage, strategies to improve soil health are not widely deployed. But, this can be short-sighted; many of the methods used to boost soil carbon storage – such as regenerative agriculture – also improve yields and long-term soil fertility.

Regenerative agriculture is a way of farming with nature, leveraging natural processes to safeguard soil health. For example, rather than relying on ploughing to aerate the soil, in regenerative farming, a thriving worm population fulfils this role. Pesticides and nitrogen fertilisers are exchanged for crop rotation, cover crops and the integrated grazing of livestock. This means that the same fields are not used repeatedly for a single species and that additional crops are planted between harvests. Therefore, carbon can be continually drawn from the atmosphere and into the otherwise barren soil and more nitrogen can be ‘fixed’ in the soil. As a result, farmers have less need for synthetic fertilisers.

But, if faced with financial insecurity, how can farmers implement these changes? Fortunately, we are increasingly equipped with financial incentive mechanisms to offer support. Indeed, carbon finance payments can act as a bridge, helping farmers to incorporate regenerative approaches. Although generating carbon finance from soil organic carbon (SOC) requires accurate measurements, emerging Measurement, Reporting, and Verification (MRV) technologies offer great potential. MRV tools can be used for both direct measurement – such as soil sampling – and remote sensing.

OUR COMMITMENT TO SOIL CARBON STORAGE

At Respira, we recognise the power of healthy soil for climate mitigation and have been early supporters of two innovative soil carbon storage projects: one focused on grassland management and the other on regenerative, arable farming.

First we partnered with the world’s largest soil carbon storage project – Northern Kenya Rangelands – which is restoring two million hectares of community-managed, grassland habitat. It is working to establish rotational grazing plans to limit the impacts of overgrazing, improve soil health and, as a result, sequester more carbon from the atmosphere.

Just last year, we welcomed a second soil carbon storage project to our portfolio. Established in 2020, Blaston Regenerative Farming Project is working to improve soil health across 230 hectares of Leicestershire farmland. Supported by independent agronomists, Indigro Ltd, Blaston Farm uses regenerative agricultural methods such as the direct drilling of arable land, crop rotation, the use of cover crops, and integrated livestock grazing. Not only do these methods enable the soil to store more carbon – but they also boost the farms overall biodiversity, long term productively and ultimately profitability.

Based on the additional carbon stored in Blaston’s soils, the project generates soil carbon certificates which represent the net amount of carbon sequestered on the farm after deducting all emissions associated with the farm’s activities. The sale of these certificates is now the second largest source of income for Blaston Farm, providing an alternative to EU subsidies in a post-Brexit Britain. In this way, regenerative agriculture is an opportunity to promote environmental and financial sustainability. While producing nutritious food, a farm can take climate action via the direct sequestration of carbon from the atmosphere.

Such projects prove that agriculture can be a solution to – not a driver of – climate change. We remain extremely committed to soil carbon storage and are optimistic of the climate mitigation potential these projects provide. With more soil carbon storage projects in the pipeline, we invite you to watch this space for announcements.

Picture credit: Northern Kenya Rangelands